Sound-reproducing device



Oct. 30, 1928. 1,689,513

A. s. ZIMMERMAN SOUND REPRODUGING DEVICE Filed Jan. 29, 1927 Inventor-i Hi Attorney.

Arthur G. Zi mmer'man,

Patented on. 30,1928.

UNITED STATES 1,689,513 OFFICE.

ARTHUR G. ZIMMERMAN, OF SCHENECTAIJ'Y, NEW YORK, ASSIGNOR TO GENERA ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

SOUND-REPRODUCING DEVICE,

Application filed January 29, 1927. Serial No. 164,620.

My present invention relates to mlflnfll reproducing apparatus of the type commonly known as loud speakers, and more particularly to a form of vibrating conical paper or fibrous diaphragm adapted to be employed in connection with such apparatus.

In the operation of loud speakers employing thin paper conical diaphragms, considerable dii'iiculty has been encountered owing l to the tendency of such diaphragms to rattle at certain frequencies. This action is due to circumferential, parasitic vibrations which are set up in the body of the cone, causing the cone to depart from a circular cross section into a distorted irregular section the displacement of which introduces rattles at certain frequencies. Some of these vibrations result from the use of a relatively long drive rod between the vibrating armature of the actuating mechanism and the cone, while others occur under the piston action of the cone, at large amplitudes. chanical limitations, it is difiicult to make the drive rod short enough to eliminate the circumferential vibrations. I have found, however, that by the provision on the cone of a plurality of properly spaced, embossed rings of a certain radius that these vibrations in the diaphragm may be prevented and rattling substantially eliminated.

While it is not unusual to employ corrugations in connection with fiat or substantially flat, metallic diaphragms, such corrugations have been employed to provide lateral stiffness in the diaphragm. In the present case the corrugations provide additional rigidity in the cone but at the same time substantially eliminate circumferential, parasitic vibrations.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. .My invention itself will best be understood by reference to the following specification when considered in connection with the ac companying drawing in which Fig. 1 represents a perspective view of the diaphragm embodying the features of my invention, while Fig. 2 is a View partly in section and partly in elevation of a portion of the diahragm and the actuating mechanism there- Referring to the drawing, I have indicated at 1 a conlcal diaphragm having an angle Owing to me- I at its apex of about 105 and a base about 7 inches in diameter. The diaphragm consists of paper about 6 mils. in thickness and is provided at its apex with an opening 2 which is adapted to be covered by a thin metal spider 3. The latter is usually cemented to the diaphragm and provides means whereby the diaphragm may be connected to suitable actuating mechanism comprising an armature 4 and a drive rod 5. The base of the cone is provided with a flange 6 out along. radial lines 7 to provide a series of tabs 8 extending around the entire flange and adapted to form a flexible support for the diaphragm. A plurality of parallelcircum ferential corrugations or embossed rings 9 are disposed on the surface of cone 1 and spaced apart suitable distances which may vary from inch to about inch from .center tocenter. Each corrugation has a radius of about 1 1; inch, and the number of corrugations may vary, say from 5 to 10. With a 105 cone having a base of '7 inches in diameter, five embossed rin s will greatly re duce rattling in the diap ragm. When a cone of this size is provided with ten rings, however, the rattling is substantially completely eliminated.

The conical diaphragm shown on the drawing may be developed with an angle at the apex of 105, and a base having a diameter of approximately 9 inches. The

cone may thenbe. cut back to provide the tab 8, the cuts being spaced approximately nch apart to rovide tabs approximately inch long. e tabs when pressed outwardly reducethe diameter of the base to approximately 7 inches and provide thereby a flexible supporting flange for the diaphragm.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a sound reproducing device, a fibrous, conical diaphragm having a series of spaced circumferential corrugations radially spaced from one another along the conical surface of said diaphragm.

2. In a sound reproducing device, a conical, fibrous diaphragm, actuating mechanism therefor comprising an armature and a drive rod connectin the armature and cone, said diaphragm belng provided with embqssed circumferential corrugations radially spaced from one another along the conical surface of said diaphragm whereby parasitic vibrations in the cone are substantially eliminated. v

3. In a sound reproducing device, a conical, paper diaphragm having a plurality of circumferential corrugations radially spaced from one another along its conical surface, each corrugation having a radius of suflicient magnitude to prevent any change in the contour of the cone during its operation.

1. In a sound reproducing device, a conical, paper diaphragm having a plurality of spacedcircumferential corrugations on the surface thereof, said corrugations being spaced apart from to inch and having a radius of approximately 4 of an inch.

5. 1n combination, a sound reproducing device comprising device comprising a conical paper diaphragm having a diameter at its base of approximately 7 inches, and a plurality of circumferential corrugations on the surface of the conical diaphragm said corrugations being spaced from inch to inch apart.

6. In combination, a sound reproducing a conical paper diaphragm having an angle at its apex of approximately 105 and a diameter at its base of approximately 7 inches, a plurality of embossed rings on said diaphragm, said rings being spaced from inch to inch apart.

In witness whereof, I have hereunto set my hand this 28th day of January 1927.

ARTHUR G. ZIMMERMAN. 

